Methods and devices used by a patient to measure a bioanalyte are well known in the art. For example, currently available technology allows a diabetic patient to monitor his own blood glucose level by drawing a blood sample with a lancing device, using an electrochemical sensor strip to capture the blood sample, and using an electronic meter connected to the sensor strip to analyze the blood sample and display the result. Until recently, relatively large sample volumes were required to be drawn, generally 3 microliters or more of blood or other biological fluid. These fluid samples are obtained from a patient, for example, using a needle and syringe, or by lancing a portion of the skin such as the fingertip and “milking” the area to obtain a useful sample volume. These procedures are inconvenient for the patient, and often painful, particularly when frequent samples are required. Less painful methods for obtaining a sample are known such as lancing the arm or thigh, which have lower nerve ending density. However, lancing the body in these preferred regions typically produces submicroliter samples of blood, because these regions are not heavily supplied with near-surface capillary vessels. The recently introduced FreeStyle™ Blood Glucose Monitoring System developed by TheraSense, Inc. of Alameda, Calif., is capable of consistently, accurately and precisely measuring sample sizes of only ⅓ microliter using this preferred “alternate site testing” (AST). U.S. Pat. No. 6,299,757, issued Oct. 9, 2001 to TheraSense, Inc. and incorporated herein by reference describes the construction and operation of the above FreeStyle system. U.S. Pat. No. 6,283,982 issued Sep. 4, 2001 to TheraSense, Inc. and incorporated herein by reference describes a lancing device that is used in the FreeStyle system.
A ⅓ microliter sample is about the size of a pinhead. Elderly patients and those with reduced eyesight and dexterity can have problems seeing and capturing such a small sample. Current testing procedures involving a lancing device, disposable lancets, meter and disposable test strips involve a lot of steps. It can be difficult for patients to remember all the steps and their proper order. Active patients testing outdoors, for example, can have a tough time juggling all of the different pieces during a test. Also, younger patients want to be able to quickly and discreetly test themselves without drawing attention with a lot of paraphernalia and testing steps.
What is needed and has not been provided by the prior art is a simpler testing method using a compact, unitary testing device.